Free flux flow (FFF) resistivity describes
how fast the vortices in a type II superconductor move in the
direction of an applied force [1]}. It is a measure of how the
momentum of the superfluid is transferred to the host lattice via
quasiparticle excitations. The
velocity-force relation expressed by the FFF resistivity has to be taken into
account in interpreting any vortex transport, be it global or local.
Since the primary source of dissipation in a type II superconductor in magnetic
field is vortex motion, FFF resistivity is also of great importance for
technical applications.
